Abstract 19128: Acute Changes in Left Ventricular Contractility Following Mitraclip Implantation Depend on Left Atrial Volume

Background: The acute hemodynamic changes following elimination of mitral regurgitation is a much discussed issue, particularly in patients with severely compromised left ventricular function where the incompetent mitral valve was regarded as a pop-off valve. Herein, we investigated the acute changes of ventricular contractility in relation to left atrial volume. Methods and results: Echocardiographic left atrial and left ventricular longitudinal strain measurements before and 3 days after the procedure were performed in 19 patients (mean age: 77.9±7.9, 47% female, 73,7% functional mitral valve regurgitation, 26,3% degenerative mitral valve regurgitation) undergoing MitraClip implantation at our institution. Procedural success with reduction in MR to grade 2+ or less was achieved in all patients. Overall there was no significant change in left atrial or ventricular global or regional longitudinal strain after the procedure. However, a strong correlation was observed between worsening in left ventricular strain and left atrial volume (r: -0.72, p<0.01), i.e. there was a greater reduction in left ventricular contractility after clip implantation in patients with larger left atrial volumes. Multivariate, linear regression analyses revealed that left atrial volume predicted the change of left ventricular longitudinal strain following MitraClip implantation (r2: -0.07, p<0.01) independently of left ventricular ejection fraction (r2: -0.05, p=0.40), mitral regurgitant volume (r2: -0.09, p=0.09) and left atrial strain (r2: -0.03, p=0.85). Discussion: Our data suggest that enlarged left atria act as a low-resistance reservoir in mitral regurgitation. As a consequence elimination of mitral regurgitation in these patients leads to worsening of left ventricular contractility whereas in smaller atria left ventricular contractility is not negatively affected by elimination of MR.